Turkish police have reportedly detained eight people in connection with the Istanbul nightclub terror attack that left 39 people dead.
The perpetrator of the attack on the Reina nightclub on the banks of the Bosphorus in the early hours of the New Year is not among those arrested by anti-terror police, the state-run Anadolu news agency reported.
Sixty-five people were also injured in the attack by the gunman, who fled the scene.
It comes after Islamic State (IS; Isis) claimed responsibility for the attack in a statement released on the Telegram app.
The gunman had "struck one of the most famous nightclubs where the Christians celebrate their apostate holiday" Isis said in the statement and described Turkey as a "protector of the cross".
Turkish police previously said the attacker may be from Central Asian countries of Uzbekistan or Kyrgyzstan.
The Turkish military said it had carried out raids on Isis-held territory in Syria. Turkish jets struck eight targets, and tanks and artillery fired on 103 targets near al-Bab, killing 22 fighters, the Turkish chief of general staff's office told Anadolu.